I have a female Golden Retriever that grooms my male Golden by cutting his hair with her front teeth... no kidding! When they are left alone together, he ends up with the worst haircut ever!! It took us awhile to realize why his hair looked so strange, and then we caught her cutting with her teeth.

She could be catching flea with your teeth and thefore cutting his hair as well. Her teeth would certainly be sharp enough to cut his hair though. I think you should put this on YouTube!

LOL! Gotta love dogs and their doggy nature.